Knopp M V, Giesel F L, Radeleff J, Von Tengg-Kobligk H
Diagnostic Radiology Department, Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA.
Invest Radiol. 2001 Oct;36(10):619-23. doi: 10.1097/00004424-200110000-00008.
Imaging of the colon is an important diagnostic procedure. Endoscopic colonoscopy and x-ray barium enemas are currently the standard diagnostic procedures. Magnetic resonance (MR) and computed tomographic colonography have been recently introduced with true three-dimensional (3D) cross-sectional imaging. Up to now, all imaging techniques have required the use of oral and/or aboral contrast agents for luminal enhancement and commonly, a relaxation medication (glucagon or N-butylscopolamine). While performing several phase I, II, and III studies with a new partially hepatobiliary excreted gadolinium-based MR contrast agent, we noted substantial intraluminal enhancement within the colon and investigated its potential for imaging.
Three-dimensional MR angiographic techniques enable imaging of large volumes. We have used these sequences to detect contrast enhancement within the hepatobiliary and gastrointestinal systems. A 3D volume of 40 x 32 x 12 cm with 42 images was acquired under breath-hold. Six volunteers were studied according to the protocol. No bowel preparation was performed and no medication given. Subsequent follow-ups of the abdomen were performed at 1, 12, 24, 36, 48, 70, and 105 hours postinjection. Gadobenate dimeglumine at 0.1 mmol/kg body weight was given intravenously. Images were assessed quantitatively and by blinded reader analysis.
Intense intraluminal contrast enhancement within the colon was seen within 24 hours in all subjects. The homogeneous enhancement was of sufficient intensity to enable 3D visualization and virtual endoscopy. The optimal time window for imaging was determined to be 16 to 50 hours postinjection.
We report for the first time the feasibility of exclusively bile-tagged MR colonography with the use of only an intravenous MR contrast that exhibits partial hepatobiliary excretion. This new diagnostic procedure will enable not only morphological assessment of the colon but also functional and pathophysiological studies on the transport kinetics of bile and stool without any preparation of the patient.
结肠成像为重要的诊断手段。目前，标准诊断方法为内镜结肠镜检查及X线钡灌肠。磁共振（MR）及计算机断层结肠成像（CT结肠成像）近来已引入真正的三维（3D）横断面成像技术。截至目前，所有成像技术均需使用口服和/或经肛门造影剂以增强肠腔显影，且通常还需使用一种松弛药物（胰高血糖素或丁溴东莨菪碱）。在使用一种新型部分经肝胆排泄的钆基MR造影剂进行多项I期、II期和III期研究时，我们注意到结肠内有明显的肠腔内强化，并对其成像潜力进行了研究。
三维MR血管造影技术可实现大容积成像。我们已使用这些序列来检测肝胆及胃肠道系统内的造影剂强化情况。在屏气状态下采集了一个40×32×12cm的3D容积，包含42幅图像。按照方案对6名志愿者进行了研究。未进行肠道准备，也未给予任何药物。在注射后1、12、24、36、48、70和105小时对腹部进行了后续随访。静脉注射钆贝葡胺，剂量为0.1mmol/kg体重。对图像进行了定量评估及由不知情的阅片者进行分析。
所有受试者在24小时内均可见结肠内强烈的肠腔内造影剂强化。均匀强化的强度足以进行3D可视化及虚拟内镜检查。确定成像的最佳时间窗为注射后16至50小时。
我们首次报告了仅使用一种经静脉注射、具有部分肝胆排泄特性的MR造影剂进行单纯胆汁标记MR结肠成像的可行性。这种新的诊断方法不仅能够对结肠进行形态学评估，还能对胆汁和粪便的运输动力学进行功能及病理生理学研究，且无需对患者进行任何准备。
